Zhang-Jie Shi

Conversion of μ-N2 complexes into nitrogenous compounds is one of the most important and challenging chemical transformations in N2 fixation. Although photochemical N2 splitting has been demonstrated, existing approaches predominantly rely on high-energy ultraviolet light that generally affords low efficiency and poor selectivity. Herein, we establish a visible-light-driven molecular photosensitization strategy that enables efficient and selective N–N bond cleavage in a dinuclear rhenium dinitrogen complex. Blue light excitation of the organic photosensitizer 4DPAIPN (2,4,5,6-tetrakis(diphenylamino)isophthalonitrile) is shown to initiate N–N scission to afford the corresponding rhenium nitride in 96% yield. Kinetic analysis of nanosecond transient absorption data through the Balzani-Scandola model indicates energy transfer from the photosensitizer to an acceptor state that lies approximately 2.31 eV above the ground state of the μ-N2-bridged dirhenium complex. This photosensitization strategy decouples light harvesting from N–N bond activation, eliminates the need for UV light, and shows broad applicability across different visible-light absorbing photosensitizers, including transition metal complexes and organic chromophores with long-lived, high-energy triplet excited-states. These findings establish dye-sensitization as a powerful strategy for visible-light-driven N–N bond cleavage for mechanistic study and the future realization of a photochemical pathway for nitrogen fixation.

C-Glycosides are recognized as ideal surrogates for natural O-glycosides owing to their excellent stability against acid-catalyzed and enzymatic hydrolysis, thus holding great application potential in drug discovery and glycochemical research. Nevertheless, the stereoselective assembly of fully saturated C-alkyl glycosides remains a formidable synthetic challenge. Herein, we disclose a one-pot reductive coupling strategy between saccharides and alkenes. This protocol integrates in situ anomeric bromination with nickel-catalyzed reductive coupling, allowing the direct C-glycosylation of partially protected saccharides that bear merely a free anomeric hydroxyl group with activated alkenes represented by ethyl acrylate.

Catalytic dinitrogen (N ₂ ) fixation commonly proceeds through metal nitride intermediates, yet their subsequent hydrogenation is often thermodynamically challenging, because the first hydrogenation step converts a stable metal nitride into a high-energy parent metal imide, where formation of a weak N-H bond provides little thermodynamic compensation. Here we report a distinct photochemical pathway for molybdenum nitride activation that enables direct nitride-to-amide conversion by hydride transfer for ammonia synthesis. Mechanistic studies show that visible-light excitation of 4DPAIPN generates an isolable dihydroacridine derivative, PAC-AcrH ₂ , whose structure was established by single-crystal X-ray diffraction. Isolated PAC-AcrH ₂ functions as a photohydride donor when pre-associated with protonated molybdenum nitride complex. Visible-light excitation promotes nitride hydrogenation through a stepwise electron-proton-electron sequence on the femtosecond-to-nanosecond timescale. This reactivity is distinct from conventional photoinduced proton-coupled electron transfer pathways and provides a kinetically efficient route toward nitride-to-amide conversion. These findings identify an unexplored mode of metal nitride activation and provide a framework for designing light-driven N ₂ reduction systems based on excited state hydride transfer.

One of the main pathways to (metal)carbene formation proceeds via the decomposition of diazo compounds, which can be triggered thermally, photochemically, or by transition-metal mediation. An alternative pathway for carbene generation from diazo compounds is the “pulling-out” N₂ by different reagents. Herein, we report an iron-mediated strategy for the homolytic cleavage of C═N bond in diazo compounds, enabling the generation of free carbenes and iron–dinitrogen complexes under mild conditions. The corresponding Fe–diazo intermediates were isolated and fully characterized by X-ray crystallography and NMR spectroscopy. Homolytic C–N bond cleavage occurs upon warming, affording a persistent (phosphino)(silyl)carbene. The kinetics of this process were further elucidated by Eyring analysis. Computational modeling highlighted the critical role of Fe → N π-backdonation in cleaving the C═N π bond. These findings establish a new mechanistic framework for metal-assisted dinitrogen extrusion from diazo compounds and offer valuable insights into controlled carbene generation.

The lithium‐mediated nitrogen reduction reaction (Li‐NRR) offers a sustainable pathway for ammonia synthesis, providing a viable alternative to the energy‐intensive Haber‐Bosch process. While most prior studies focused on solution‐phase optimization, we introduce a transformative electrode engineering strategy via the rational design of triethylammonium germanate‐modified copper (Cu/TEG) electrodes. Multi‐technique characterization reveals the formation of the Li ₁₅ Ge ₄ alloy during the Li‐NRR. Electrochemical measurements combined with DFT calculations demonstrate that the Li ₁₅ Ge ₄ alloy simultaneously facilitates lithium deposition and shifts the N ₂ adsorption energy more exothermic. Most importantly, this interfacial engineering enables a Faradaic efficiency (FE) of up to 92.5% at an unprecedented N ₂ pressure as low as 4 bar and with minimal overpotential relative to the onset of lithium deposition. This synergy minimizes energy losses, achieving the highest reported pseudo‐energy efficiency value (17.6%) in a batch cell to the best of our knowledge. Overall, this work establishes dual‐function interfacial engineering via lithium‐germanium alloy formation as a breakthrough strategy, moving beyond conventional solution‐phase optimization to provide a new approach for efficient electrochemical nitrogen fixation.

The lithium‐mediated nitrogen reduction reaction (Li‐NRR) offers a sustainable pathway for ammonia synthesis, providing a viable alternative to the energy‐intensive Haber‐Bosch process. While most prior studies focused on solution‐phase optimization, we introduce a transformative electrode engineering strategy via the rational design of triethylammonium germanate‐modified copper (Cu/TEG) electrodes. Multi‐technique characterization reveals the formation of the Li ₁₅ Ge ₄ alloy during the Li‐NRR. Electrochemical measurements combined with DFT calculations demonstrate that the Li ₁₅ Ge ₄ alloy simultaneously facilitates lithium deposition and shifts the N ₂ adsorption energy more exothermic. Most importantly, this interfacial engineering enables a Faradaic efficiency (FE) of up to 92.5% at an unprecedented N ₂ pressure as low as 4 bar and with minimal overpotential relative to the onset of lithium deposition. This synergy minimizes energy losses, achieving the highest reported pseudo‐energy efficiency value (17.6%) in a batch cell to the best of our knowledge. Overall, this work establishes dual‐function interfacial engineering via lithium‐germanium alloy formation as a breakthrough strategy, moving beyond conventional solution‐phase optimization to provide a new approach for efficient electrochemical nitrogen fixation.

Diboryldiazomethanes, featuring dual boryl substitution that can simultaneously stabilize and diversify the diazo carbon center, represent an appealing yet largely inaccessible class of diazo compounds. Here, a preorganized B₂N₂C scaffold is converted into a diboryldiazomethane via N₂O-mediated diazo transfer. Reactivity studies with Lewis acids reveal two distinct binding sites within the diazo unit, enabling selective engagement of the terminal nitrogen versus the carbon center. In contrast, methoxide triggers addition across a B-C bond with opening of the five-membered ring to furnish a monoboryl diazo derivative. All new species were fully characterized by multinuclear NMR spectroscopy and single-crystal X-ray diffraction (SC-XRD). These findings establish a stable entry to diboryldiazo chemistry and define a tunable reactivity model for main-group-controlled diazo platforms.

We report highly Lewis-acidic diboranes that reversibly bind halides via cavity-controlled recognition, display dynamic host–guest behavior, and invert the conventional halide (Br/Cl) leaving-group order in diborane-catalyzed reactions.